class Solution {
public:
	vector<vector<int>> generate(int numRows) {
		vector<vector<int>> vv;
		vv.resize(numRows);
		for(int i = 0; i < numRows; ++i)
        {
            vv[i].resize(i + 1, 0);
            vv[i].front() = vv[i].back() = 1;
        }
        for(int i = 0; i < numRows; ++i)
        {
            for(int j = 0; j < i + 1; ++j)
            {
                if(vv[i][j] == 0)
                    vv[i][j] = vv[i - 1][j - 1] + vv[i - 1][j];
            }
        }
		return vv;
	}
};